Well for those who were in doubt or simply tired of all the speculation surrounding Katsura-san's gender. After some sleuthing, I dug up these two pieces of evidence which will undoubtedly prove something.

Exhibit A <---Link

This is indirectly revealing that Katsura Hoshino's gender is female, as the person says "Her"

Exhibit B:



Since we now know Katsura-san is female, she is the picture on the bottom right. As such, this wraps up this little mystery.